Cooking and proceeding quality of onions (Allium cepa) cultivated in Hokkaido

Abstract

In Japan, onion is mainly produced in Hokkaido. The quality of onion has been improved by breeding or crossing, and the production is increasing. Although cooking and proceeding properties of the onion have been reported in a few papers, the cultivars used in these papers are often unclear. Therefore, we employed 13 cultivars of onion currently cultivated in Hokkaido, and studied on individual cooking and proceeding properties. The results obtained were summarized as follows; All cultivar of onion bulb were levels of solid contents (9-11%) and reducing sugar (4-5 %) showed suitability of processing to saute and powder. (2) Brix percent of onion bulbs were 7-11%. (3) Phenol contents were 150mg/100 g in red type, and 70-100mg/100 g in yellow type. The cultivars which contain high phenol were evaluated with that it is bitter when it was sauted. The correlation was established between phenol contents and color value (a* and b*) of onion bulb, the green and yellow degree was high for onion containing high phenol. But phenol contents did no affect to color of sauted onion. (4) Pyruvate production was 5-9μmol/ g, this was divided into medium pungency. There was the positive correlation between pyruvate production and pungency, and negative correlation between pyruvate production and sweetness. There was no correlation between sweetness and free sugar, Brix, solid content.